Conventionally in the medical field, a flexible medical tube has been used as a pipe constituting an extracorporeal circulation circuit or an auxiliary circuit for body fluid such as blood or a transfusion line of drug solution and the like. Also, a clamp device made of resin moldings has been used so as to make the medical tube closable at a desired position as needed.
Such a clamp device, as shown in Unexamined Japanese Patent Application Publication No. JP-A-2003-235971 (Patent Document 1), has a structure where a first plate part and a second plate part connected at a curved portion and each provided with a compressive protrusion on each opposing surface. Then, the medical tube is retained in a closed state being compressed between the compressive protrusions by the elastic deformation of the curved portion to lock the first and second plate parts at a location close to each other.
Meanwhile, it often requires promptness and reliability in the medical practice to switch the medical tube between a connected state and a shutoff state.
However, using the conventional clamp device, the medical tube is displaced off to the side from the compressive protrusions to pose a risk of incomplete shutoff, which used to require a careful handling.
In order to prevent the medical tube from being displaced off to the side, one option is to form a pair of side walls on both sides of one of the first and second plate parts in the width direction to prevent the displacement. However, once the pair of side walls are formed to prevent the displacement, relative displacement between the first and second plate parts in the direction of bringing them closer to each other is interfered by the compressive protrusion of the other plate part abutting against the end surfaces of the pair of side walls during the compressive operation of the medical tube, posing a risk of detrimental impact on the prompt closing operation of the medical tube.